TORONTO — Environmental groups are appealing a Federal Court decision that refused to overturn an environmental assessment of Ontario Power Generation’s proposal to rebuild four aging nuclear reactors at the Darlington power plant.

The appeal has been launched by Greenpeace, Canadian Environmental Law Association (CELA), Lake Ontario Waterkeeper and Northwatch, which argue that the environmental assessment had major deficiencies and did not satisfy the requirements of the Canadian Environmental Assessment Act.

“In our view, the environmental assessment did not properly address the project’s potential impacts on fisheries, the risks posed by nuclear waste storage and management, or the environmental effects of a reactor accident causing large radioactive releases into nearby communities,” said Shawn-Patrick Stensil, an energy analyst with Greenpeace. “These risks must be fully considered in order to make an informed decision whether this project should move forward.”

Lawyers from Ecojustice and CELA filed the appeal on behalf of the four groups in late December. The decision under appeal was released in late November.

“Our clients are asking the Court of Appeal to reverse the lower court ruling, and to stop this project from proceeding until the environmental assessment is completed in compliance with the Act,” said Kaitlyn Mitchell, Ecojustice staff lawyer. “When it comes to large-scale projects like the proposed rebuild, it’s critical that the public — and federal decision-makers — have a proper understanding of what risks it may pose to human health and the environment, and whether such risks can be fully mitigated or avoided.”

"Lake Ontario is a vital part of daily life for nine million people. It can and should be protected from the impacts and risks posed by operating rebuilt reactors at the Darlington site. That is what a fulsome environmental assessment promises," said Mark Mattson of Lake Ontario Waterkeeper.

In a separate ruling issued in May 2014, the Federal Court set aside an OPG licence to undertake site preparation to build new nuclear reactors at the Darlington location. In this judgment, the Court agreed with Greenpeace, CELA, Lake Ontario Waterkeeper and Northwatch that the environmental assessment for the new build project did not meet the requirements of the Canadian Environmental Assessment Act because it failed to reasonably consider three key issues: hazardous chemical emissions; management of nuclear waste; and the impacts of a severe multi-reactor accident leading to large off-site releases of radioactive substances. This judgment has since been appealed by Ontario Power Generation, Canadian Nuclear Safety Commission, and the Attorney General of Canada.